2015 ISAKOS Biennial Congress ePoster #1414

Patient Specific Guides for Total Knee Arthroplasty are Ready for Prime Time. A Single Surgeon Experience with Different Systems

Martijn Schotanus, PhD,MSc, BEng, Sittard-Geleen, Limburg NETHERLANDS
Nanne P. Kort, MD, PhD, Roosteren, Europe NETHERLANDS

Orbis Medisch Centrum, Sittard-Geleen, Limburg, NETHERLANDS

FDA Status Not Applicable

Summary: Our paper illustrates that this simplified surgical technique for TKA is safe and effective with acceptable outcome.

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Abstract:

Purpose

This prospective controlled study on patient specific matched guides (PSG) between different manufacturer and conventional technique for the implantation of total knee arthroplasty (TKA) has been undertaken to address the following research questions: firstly, is there a significant difference in outliers and alignment >3° deviation in the frontal and lateral plane between PSG and conventional TKA? Secondly, is there a significant difference between four individual different PSG systems and thirdly between cut- and pin PSG?

Methods

A total of 57 knees operated with PSG TruMatch n=15, Visionaire n=13, PSI n=14 and Signature n=15) were compared with a group operated with conventional instrumentation (n=45). Percentages >3° deviation of the preoperative planned biomechanical axis of the leg (HKA), lateral femur (flexion/extension ;LFC) and tibia (posterior slope; LTC) and frontal femur (varus/valgus; FFC) and tibia (varus/valgus; FTC) of the individual implant components were defined as outliers. All post operative measurements on long-standing and lateral x rays were done by two independent assessors. Baseline demographics and perioperative outcome were analysed with a parametric one-way ANOVA. Intra- and Interclass Correlation Coefficient (ICC) was calculated to check for intra- and inter observer reliability. Fisher exact test was used to test differences of proportions. P-value was considered to be statistically significant at P=0.05 for all statistical analysis.

Results

All radiographic measurements between both observers were reliable and ICC were excellent. There was no statistically significant difference in outliers of biomechanical axis between the PSG (n=57) and Conventional TKA (n=45). With regard to the individual components, percentage of outliers of the FFC, LFC and the LTC were statistically significant different in favour of the PSG group. (p<0.05) Regarding the individual PSG systems, there were no statistically significant differences regarding the outliers. Although, the mean biomechanical axis HKA, FFC, FTC, LTC were statistically significant different. (p<0.001) The PSG group subdivided into cut- and pin PSG were not statistically significant different regarding the outliers. However, the mean FFC and LTC were statistically significant different. (p<0.05)

Conclusion

Based on our experience, the patient specific matched guides are safe and easy to use. The PSG group show better radiological outcome compared to the conventional group. Whether these differences are clinically relevant is questionable. The long-term clinical outcomes and survival rate will identify if one or the other is superior.